Ryanair has branded as “false” claims passengers are being forced to pay up to £21 for a seat booking if they want to access an e-boarding pass.
Some irate customers claimed they had to pay to book a seat before receiving the boarding pass online.
When they declined to book the seat or pay a fee, the passengers claimed they were told to queue for a paper pass on arrival at the airport.
Ryanair on Monday issued a strong denial this practice was in place.
“This is false. There is no charge for a Ryanair digital boarding pass – ever,” a spokesperson for the Michael O’Leary-run budget airline said.
“All Ryanair passengers can pay for a reserved seat if they so wish or if passengers wish to avoid this seat fee, they can select a randomly allocated seat entirely free of charge.”
Vivien Lovrin told the London Mail on Sunday she booked to fly from London to Germany last Thursday and having opted not to pay extra to reserve a seat, proceeded to check-in with a randomly allocated spot.
After filling in details, she said the Ryanair app told her: "Check-in done! Get your boarding pass now and avoid queuing at the airport by adding a seat."
One traveller told the BBC staff at the airport check-in desk said the new policy was only for the last 20 passengers checking in for the flight online, and the charge had been introduced in the past few days.
Martyn James, a computer rights expert, said the claimed new charges could be an error with Ryanair's computer or booking systems.
"If this new charge is true, then it's something of a false economy for Ryanair, as they'll need an awful lot more staff on the check-in desks to print off all of those boarding passes," he said.